Crimping textile strands



April 1962 R. w. LIST ET AL CRIMPING TEXTILE STRANDS Filed Nov. 27, 1956 mtr n zL r eWw M w k flm m w Unite States Patent Filed Nov. 27, 1956, Ser. No. 624,613 Claims. (Cl. 28-4) This invention relates to stuifer-crimping of textile strands, concerning especially improved confinement thereof in the crimping chamber.

The major elements of the well-known type of strandcrimping apparatus designated generally as stuifercrimper include a chamber to receive and confine a strand, a movable (e.g., hinged or reciprocable) obstruction at or near the outlet end of the chamber to impede passage of the strand, and a pair of rolls at the inlet end of the chamber to feed or stuff the strand into the chamber. In such devices, much of the back pressure applied in order to confine the strand in the chamber sulficiently to impart a crimp to it (and to its component filaments) is dissipated as frictional force against the walls of the chamber; moreover, drag imposed by the impeding or back-pressure device on the components of the strand when withdrawn thereagainst as a lengthwise traveling strand, rather than as a confined accumulation or bunch of crimped material, is so great as to impair or lessen the acquired crimp.

A primary object of the present invention is improved staffer-crimping of textile strands. An object is reduction in the travel of strands while under crimping infiuence in a stulfer-crimper. A particular object is application of crimping back pressure in the near vicinity of the feeding rolls of a stuifer-crimper. Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

, FIG. 1 is a front elevation of apparatus (shown partially cut away) constructed and operated according to the present invention; FIG. 2 is a side elevation of the apparatus of FIG. 1; FIG. 3 is a horizontal section taken at 3-3 of FIG. 2; and FIG. 4 is a fragmentary side sectional elevation taken at 44 of FIG. 1.

In general, the objects of the present invention are accomplished by forcibly feeding a textile strand into a crimping zone, continuously impeding, at a fixed location relative to the crimping zone, the passage of the strand from the crimping zone by means of a unidirectionally movable impeding element having an endless strand-engaging peripheral surface effective to accumulate and crimp the strand in the crimping zone, and releasing the accumulated and crimped strand from the crimping zone by directing the force of the crimped strand against the impeding element andthereby moving the'impeding element. The invention contemplates application of the impeding force to the unidirectionally moving strand by impeding means moving likewise. As particular apparatus for practicing the above process, this invention comprehends strand-confining means having a bore adapted to receive a textile strand in one end and to emit it at the other end and a strand-impeding element intercepting the bore and adapted to move therealong and to retard passage of the strand therethrough.

FIG. lshows apparatus according to the present invention as viewed from the front. Prominently visible are base plate 1 and top plate 2 extending horizontally, front plate or facade 3 extending vertically from the bottom plate to and above the top plate, a pair of feed rolls 4, 4 located side by side .in front of the facade between the respective levels of the two plates, and a crimping tube 5 extending from above the nip of the feed rolls to a level well above the top of the facade. Four thumbscrews 6 hold washers 16 against the front of the tube to retain it in place against the front of the facade. A portion of drive motor 19, which is mounted on the top plate, in visible extending to the side from behind the facade. Also apparent, located just below the roll nip, are infeeding block 7 and clip 8; the block is retained against the facade by thumbscrew 13 threaded into the facade through slot 23 in the lower part of the block. At the left side, screw 14 holds the clip against the block in like manner, i.e., clip 8 is provided with a flange having a slot through which screw 14 is threaded into the side of block 7. The block and clip together form a feed guide for strand entering the nip.

Strand 1t), seen to pass between the block and the clip and into the nip of the feed rolls, enters the yoke-like bottom of the tube (shown in broken lines) and passes upward through the bore of the tube, where it is crimped. Part of the tube is cut away in this view to reveal accumulation 20 of crimped yarn in bore 15 of the tube and to show shoulder 25, above which the bore enlarges, about halfway between the level of the roll tops and the top plate. From the top of the tube, crimped strand 10' passes about idler roll 9, through spring-tensioner 11 (shown schematically) and into the nip of forwarding rolls 12, 12'.

Visible at the left of the facade are respective upper and lower shafts 17 and 18 carrying rotatable pulley 27 and stationary sheave 28, respectively, over both of which asses belt 29. The right end of the upper shaft protrudes at the right of the facade through adjacent bushing 37; bushing 37' surrounds the shaft adjacent the facade at me lert side of the viewer.

FIG. 2 shows the apparatus of the preceding view from the right side. In addition to elements previously visible, this view reveals motor shaft 31 extending rearward and carrying drive pulley 32, about which belt 33 passes. This drive belt also passes about pulley 36 carried on axle 34, which carries roll 4 at the other end. Gear 33 affixed to this axle meshes with a like gear on the axle (hidden in this view) for the other roll, both axles being rotatably supported in back plate 30 rising from the base plate.

At the left side of FIG. 2 belt 29 can be seen passing about sheave 28, whose shaft is bound in pillow block 41 retained against the back of the facade by upper and lower cap bolts 42, 42'. The upper end of the belt passes behind a protruding portion of toothed wheel-like element 45, which is affixed to shaft 17. The remaining views further illustrate this element, which functions to impede passage of the strand accumulation upward through the bore of the crimping tube.

FIG. 3 shows the apparatus sectioned substantially horizontally under the top plate at 33 of FIG. 2. Bore 15 of the crimping tube is partly obstructed by the gear-like strand-impeding element, which passes through opening 47 in the facade and slot 49 in the back of the crimping tube so as to intercept the bore transversely (from the rear); the accumulation of crimped strand is omitted from this view to reveal the intercepting portion of the gear with the inside wall of the tube surrounding it. Axles 34, 34' from respective feed rolls 4, 4 extend rearward through the facade to and through supporting back plate 30. Axle 34' carries driven gear 38 in mesh with drive gear 38; in the interest of clarity the drive belt is omitted from this view, while the driving pulley (located above the plane of the section( appears in phantom.

FIG. 4 is a central sectional view taken (as indicated at 44 of FIG. 1) in the same direction as FIG. 2. The infeeding strand is visible proceeding straight upward through the guide formed by block 7 and clip 8 to and through the roll nip and into the bore of the crimping tube (by which level a departure from rectilinearity of the yarn configuration is apparent), and then upward through the tube. In this view the gear-like strand-impeding element is seen to intercept the bore to at least about the depth of one tooth and approximately one-third to one-half the bore depth. The teeth themselves are raked opposite to the direction of yarn travel. The strand accumulation, which is compressed tightly at and below the level of interception, loosens perceptibly at higher levels, as is especially noticeable at and above the shoulder of the bore. The top portion of the tube shows no such accumulation but only the individual crimped strand, which is being withdrawn lengthwise upward. In addition to the cap bolt extending through the pillow block into the back of the facade, this View also indicates in broken lines setscrew t) threaded through the block and against shaft 18 to bind the axle of the stationary sheave.

Operation of the described and illustrated apparatus is readily understood. The strand to be crimped, which usually is supplied from a bobbin or pirn (not shown) located below the feed rolls, is threaded manually between the rolls, with its end inserted in the inlet of the crimping tube directly above the nip of the feed rolls. The motor is started, whereupon the rolls rotate to feed the strand into the tube, which soon becomes filled up to the level of the intercepting gear, whereupon the back pressure exerted upon the accumulated strand increases markedly. Thereafter, upon entering the tube, the strand bends back and forth and from side to side as it is stuffed into the bottom end of the tube, as is customary in previously known stufler-crimpers, and these various deviations of the strand from the original rectilinear configuration are emphasized to the extent ofbecoming a relatively permanent crimp.

With continued operation, as more and. more strand is fed upward in the crimping tube, the accumulation of crimped strand begins to force its way on upward through the tube, rotating the gear that partially obstructs the passage. At all times, friction of slippage between belt 29 and either rotatable pulley 27 or stationary sheave 28 (whichever exerts less force on the belt) retards the rotation to provide the essential crimping impedance. Of course, the amount of applied impedance is adjustable, as by variation in the tension applied to the belt. The teeth of the gear, being raked oppositely to the direction of rotation, emerge cleanly from the leading portion of the crimped strand accumulation, which proceeds upward through the bore of the tube free of the back pressure previously applied to it, while the following portions of the strand accumulation below the level of the impeding gear are subjected uniformly to the same unvarying back pressure.

Upon reaching the enlargement in the bore provided by the inner shoulder of the tube, the accumulated strand loosens appreciably, and no further crimping force is applied from there upward. The end of the strand, which is to be threaded through the spring-tensioner and the forwarding rolls, now may be grasped in any suitable manner and be withdrawn for that purpose, or this step may be deferred until the end emerges from the top of the tube. Alternatively, the strand may be threaded entirely through the apparatus (and on to conventional windup mechanism) preliminary to initiation of the feedroll drive; such threadup can be facilitated, as will be apparent, by fabricating the crimping tube with all or part of one side readily removable.

An important feature of this invention is concentration of the region within which the strand is subjected to the crimping influence. Not only is the impedance-providing element (shown in gear form). located quite close to the inlet of the crimping chamber (shown in tubular form), but the bore of the chamber or tube enlarges immediately above the impeding or obstructing location so as to assure, prompt release of the strand from the force applied to crimp it. This minimizes the distance through which the strand passes compressed against the wall of the crimping chamber, which itself preferably has a very low coefficient of friction, as may be obtained by a satiny or similar metal finish of the inside wall, oras preferred according to this inventionby a coating of polytetrafluoroethylene or the like on all or part of the wall. Furthermore, the crimped yarn is relieved from the impeding force quickly and evenly while still accumulated or bunched together, eliminating the disadvantage (inherent in conventional stutfer-crimpers) of dragging withdrawal of the crimped strand longitudinally past an impeding element, which tends to remove the crimp, as will be apparent to one familiar with that art.

Various apparatus modifications may be made that do not involve a departure from an embodiment of the present inventive concept. Of course, as suggested above for the crimping tube itself, one or more of the various elements may be fabricated in a multiplicity of pieces for convenience in manufacture, assembly, or maintenance; alternatively, two or more elements (such as the facade and the crimping tube, for example) may be combined into a single housing or similar element. The shape of the crimping chamber itself may be altered; for example, it may flare outward toward the end from which the strand exits, and the shape of the opposite or intake end of the tube, whose side walls terminate in vertexes closely approaching the peripheral surfaces of the respective feed rolls, may be varied as desired for adequate doctoring of the rolls, i.e., ensuring entrance of all the fed strand into the tube; similarly, the shape of the infeeding guide, which also enters closely toward the nip of the rolls, may be varied for a like purpose. If desired, the front or one side wall of the tube or chamber may be made of glass or transparent plastic to permit observation of the crimping as it occurs.

The dimensional relation between the feed-roll radius and the bore of the tube (or similar crimping chamber) may be altered throughout a wide range, but for best results the level at which maximum interception of the bore by the gear or other strand-impeding element occurs is separated from the chamber inlet by a distance no greater than a single radius of the feed rolls. Too, it is desirable that the effective release location of the strand accumulation from the crimping influence, as here provided by increase in the size of the bore, be located similarly closely to the strand-impeding location. Of course, loosening of the four thumbscrews permits vertical (and slight horizontal) adjustment of the position of the crimping tube; the position of the infeeding guide with respect to the roll nip may be varied in like manner by means of its retaining screw. Suitable provision may be made for adjusting the location of other elements, such as the feed rolls relative to one another and the degrees of insertion of the impeding element in the bore of the crimping chamher.

The strand-impeding element (shown here in gear-like configuration) may be constructed otherwise with similar effect, although the configuration illustrated and described above is preferred at present. Instead of having teeth, this element may be similarly wheel-like in shape and may present an otherwise irregular, frictionally effective surface to the strand; alternatively, a chain may replace the gear or wheel. Whatever configuration of impeding element may be employed, its peripheral surface will be movable in the direction of passage of the strand through the bore of the crimping chamber, at a determinable rate sufliciently slow to impose considerable retarding force on the confined accumulation of strand. As indicated above, the impeding element need not occupy or obstruct more than a minor portion of the transverse cross section of the bore, either widthwise or depthwise, although it may be set deeper if desired. More than one such e1e-' ment may-enter the crimping chamber oppositely, or a multiplicity of such elements arranged contiguously may constitute (for part of the passageway) the crimping chamber itself; however, use of a single strand-impeding element appears preferable from the standpoint of simplicity of construction and operation and of minimum interference with passage and removal of the crimped strand in undegraded condition.

The impedance offered to the passage of this strand accumulation will depend not only upon the inset, configuration, and number of the strand-impeding element(s), but also upon the retarding force applied thereto, as by the illustrated belt arrangement. Of course, the tighter the belt, the greater the impedance, and shims may be inserted between the pillow block and the sup porting facade to increase the belt tension. Alternatively, the relative sizes of the pulley and sheave or the sizeof the belt may be varied. Even more simply, the illustrated endless belt may be replaced by a length of belting or the like affixed at one end to the facade, as by one of the bolts, then passing over the pulley, and carrying at the other end a weight effective to force the belting against the pulley and thereby retard its rotation to the desired extent. As yet another variation in the retarding means, the shaft of the strand-impeding element may carry (instead of, or in addition to the pulley) vanes whose rotation would be impeded by the surrounding air or by liquid in a damping chamber, as will be apparent. Regardless of the design of impeding element or retarding means, the desired impedance and retardation will be dependent upon the strand as well as the apparatus; the proper setting will be determined readily by observation of the results of slight changes made therein.

The procedure described above requires no control of the height to which the strand accumulates above the impeding element in the crimping chamber, inasmuch as throughout a major part of the passage the strand is not subjected to further external crimping influence; of course, for convenience the forwarding rate will be synchronized with the feeding rate to prevent overflow of the tube and, contrariwise, withdrawal of the strand directly from a level below that of the impeding gear or similar element. The processing rate can be controlled effectively by varying the retardation applied to the impeding element, as well as by varying its size, shape, or degree of insertion into the bore of the chamber.

The present invention is useful in the crimping of all manner of strands, whether made up of natural or synthetic materials, primarily those composed Wholly or in large part of continuous filaments, which usually are processed in relatively untwisted condition, although it is adapted also to use with highly twisted strands and those having staple components. Strands having thermoplastic characteristics are usually well suited to the practice of this invention, although it does not require any elevated temperature; moreover, immediate application of the invention to crimping of nylon multifilament should not obscure its relative independence of the chemical composition of the strand components,

The claimed invention:

1. A process of crimping a textile strand comprising feeding the strand into a crimping zone, continuously impeding, at a fixed location relative to the crimping zone, the passage of the strand from the crimping zone by a unidirectionally movable impeding element having an endless strand-engaging periphery to accumulate and crimp the strand in the crimping zone, and releasing the accumulated and crimped strand from the crimping zone by directing the force of the crimped strand against the impeding element to move the same.

2. A process of crimping a textile strand comprising feeding the strand into a crimping zone, continuously impeding, at a fixed location relative to the crimping zone, the passage of the strand from the crimping zone by a rotatable impeding element to accumulate and crimp the strand in'the crimping zone, and releasingthe accumulated and crimped strand from the crimping zone by directing the force of the crimped strand against the impeding element to rotate the same.

3. The process defined in claim 2, including applying a uniform impeding force to the strand by the rotatable impeding element by applying a uniform yielding resistance to the rotation of the impeding element to crimp and accumulate the strand in the crimping zone.

4. A process of crimping a textile strand comprising feeding the strand into a crimping zone, impeding the passage of the strand through the crimping zone by a rotatable impeding element, and frictionally retarding the rotation of the latter to accumulate and crimp the strand in the zone, the force of the crimped and accumulated strand in the zone overcoming such frictional retarding to rotate the element and release the strand from the zone.

5. A stuffer-crimper comprising a pair of strand-feeding rolls, a crimping tube having one end juxtaposed to the nip of the rolls and with an opening intermediate its ends, and a gear-like strand-impeding element rotatably mounted on an axis essentially perpendicular to the axis of the tube with its peripheral surface characterized by protruding teeth raked opposite to the direction of rotation, fitting within the opening, and extending into the inside of the tube.

6. The apparatus of claim 5, in which the location of maximum extent of the strand-impeding element into the crimping tube is separated from the nip of the rolls by a distance at most equal to the roll radius.

7. The apparatus of claim 5, including means for frictionally retarding rotation of the strand-impeding element, whereby passage of a strand fed into the tube and against the strand-impeding element by the strand-feeding rolls is opposed with a force independent of the feeding rate.

8. In a stulfer-crimper, the combination of a wheellike element rotatably mounted on a fixed axis, a pair of strand-feeding rolls rotatably mounted on axes located a constant distance from and substantially perpendicular to the axis of the wheel-like element, confining means forming an enclosed passageway between the nip of the feed rolls and the wheel-like element and intercepting part of the peripheral surface of the wheel-like element, and means associated with the wheel-like element and adapted to impart thereto a substantially unvarying frictional force effective to oppose rotation thereof by strand fed into and through the passageway.

9. In strand-crimping apparatus having a tube-like chamber into and through which the strand to be crimped is fed in continuous manner, the improvement comprising strand-impeding means including a wheel-like element fixedly located with part of its peripheral surface intercepting the chamber and rotatably mounted to move therein, upon contact with the strand, in the direction of passage of the strand therethrough and a frictional retarding element continuously in contact with the wheellike element and adapted to impart thereto a substantial- 1y unvarying frictional force effective to retard the rotation thereof without altering the direction of rotation and thereby impede passage of the strand through the chamber.

10. Apparatus comprising strand-confining means having a bore adapted to receive a textile strand in one end, to accumulate it temporarily therein, and to emit it from the other end; a fixedly mounted wheel-like strand-impeding element intercepting the bore and adapted to contact the strand therein, to impede passage of the strand therethrough, and to move therealong in impeding contact with the strand in the direction of strand travel; friction-generating means continuously connected to the strand-impeding element and adapted to impart thereto a substantially unvarying frictional force effective to permit movement of the strand-impeding means only upon sufliciently forcible contact of the strand against the References Cited in the file of this patent UNITED STATES PATENTS Tait Oct. 1 9, 1954 Wicker Jan. 11, 1955' Pfau May 28, 1957 Mariani et a1. Ian. 21, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,02%619 April 3 1962 Ralph W. List at al.

It is hereby certified that error appears in the above numbered patd Letters Patent should read as ent requiring correction and that the eel corrected below.

Column 2, line T for "in" read is line 68, for "section(" read section) column 3, line 18 for "bolt" read bolts column 4 line 56, for "degrees" read degree Signed and sealed this 17th day of July 1962.

(SEAL) Attest:

DAVID L. LADD ERNEST W. SWIDER Attesting Officer Commissioner of Patents 

